"Committed_by_peb"

src/GF/Parsing/CFG/PInfo.hs

@@ -0,0 +1,95 @@
+---------------------------------------------------------------------
+-- |
+-- Maintainer  : PL
+-- Stability   : (stable)
+-- Portability : (portable)
+--
+-- > CVS $Date: 2005/04/11 13:52:52 $ 
+-- > CVS $Author: peb $
+-- > CVS $Revision: 1.1 $
+--
+-- CFG parsing, parser information
+-----------------------------------------------------------------------------
+
+module GF.NewParsing.CFG.PInfo where
+
+import GF.System.Tracing
+import GF.Infra.Print
+
+import GF.Formalism.Utilities
+import GF.Formalism.CFG
+import GF.Data.SortedList
+import GF.Data.Assoc
+
+----------------------------------------------------------------------
+-- type declarations
+
+type CFParser c n t = CFPInfo c n t 
+		    -> [c]             -- ^ possible starting categories
+		    -> Input t         -- ^ the input tokens
+		    -> CFChart c n t
+
+------------------------------------------------------------
+-- parser information
+
+data CFPInfo c n t
+    = CFPInfo { grammarTokens        :: SList t,
+		nameRules            :: Assoc n            (SList (CFRule c n t)),
+		topdownRules         :: Assoc c            (SList (CFRule c n t)),
+		bottomupRules        :: Assoc (Symbol c t) (SList (CFRule c n t)),
+		emptyLeftcornerRules :: Assoc c            (SList (CFRule c n t)),
+		emptyCategories      :: Set c,
+		cyclicCategories     :: SList c,
+		-- ^ ONLY FOR DIRECT CYCLIC RULES!!!
+		leftcornerTokens     :: Assoc c (SList t)
+		-- ^ DOES NOT WORK WITH EMPTY RULES!!!
+	      }
+
+--buildCFPInfo :: (Ord n, Ord c, Ord t) => CFGrammar c n t -> CFPInfo c n t
+
+-- this is not permanent...
+buildCFPInfo grammar = traceCalcFirst grammar $
+		       tracePrt "cf parser info" (prt) $
+		       pInfo' (filter (not . isCyclic) grammar)
+
+pInfo' grammar = CFPInfo grToks nmRules tdRules buRules elcRules emptyCats cyclicCats leftToks 
+    where grToks          = union [ nubsort [ tok | Tok tok <- rhs ] | 
+				    CFRule _ rhs _ <- grammar ]
+	  nmRules         = accumAssoc id [ (name, rule) | 
+					    rule@(CFRule _ _ name) <- grammar ]
+	  tdRules         = accumAssoc id [ (cat,  rule) | 
+					    rule@(CFRule cat _ _) <- grammar ]
+	  buRules         = accumAssoc id [ (next, rule) | 
+					    rule@(CFRule _ (next:_) _) <- grammar ]
+	  elcRules        = accumAssoc id $ limit lc emptyRules
+	  leftToks        = accumAssoc id $ limit lc $ 
+			    nubsort [ (cat, token) | 
+				      CFRule cat (Tok token:_) _ <- grammar ]
+	  lc (left, res)  = nubsort [ (cat, res)   | 
+				      CFRule cat _ _ <- buRules ? Cat left ]
+	  emptyRules      = nubsort [ (cat, rule)  | 
+				      rule@(CFRule cat [] _) <- grammar ]
+	  emptyCats       = listSet $ limitEmpties $ map fst emptyRules
+	  limitEmpties es = if es==es' then es else limitEmpties es'
+	      where es'   = nubsort [ cat | CFRule cat rhs _ <- grammar, 
+				      all (symbol (\e -> e `elem` es) (const False)) rhs ]
+	  cyclicCats      = nubsort [ cat | CFRule cat [Cat cat'] _ <- grammar, cat == cat' ]
+
+isCyclic (CFRule cat [Cat cat'] _) = cat==cat'
+isCyclic _ = False
+
+
+----------------------------------------------------------------------
+
+instance (Ord n, Ord c, Ord t) => Print (CFPInfo n c t) where
+    prt pI = "[ tokens=" ++ sl grammarTokens ++
+	     "; names=" ++ sla nameRules ++ 
+	     "; tdCats=" ++ sla topdownRules ++
+	     "; buCats=" ++ sla bottomupRules ++ 
+	     "; elcCats=" ++ sla emptyLeftcornerRules ++
+	     "; eCats=" ++ sla emptyCategories ++
+	     "; cCats=" ++ sl cyclicCategories ++
+	     "; lctokCats=" ++ sla leftcornerTokens ++ 
+	     " ]"
+	where sla f = show $ length $ aElems $ f pI
+	      sl  f = show $ length $ f pI